get a mustang ho motor it has like 220 horsepower and it weighs like 50 pounds less than the datsun l6 put aluminum heads cam headers intake good carb or fuel injection a T5 manula overdrive you will have about 350 to 400 with about 30mpg and be very very very fast. i would personaly put a 302HO put a cam good intake and exhoust cam stock heads valves and everythings else and get like 330 horsepower and 30-35mpg with a overdrive